3d print problem

[benmorgan]

Hello All
Got a little problem that I am hoping your combined wisdom can help me solve.
My model looks smooth and all good to me in sketchup.

Bur when I import to shapeways.com to 3d print, it looks dented and has a triangular hole in the middle.
see the model here:

http://shpws.me/qWLL

Any suggestions to fix this problem?

Thanks

[Rich O Brien]

Can't view link

[dukejazz]

Can't view your link also - duke

Have you triangulated your model?
Have you reverse faces or size model right?

This may help you
Model Verification for 3d printing | http://sketchucation.com/forums/viewtopic.php?f=15%26amp;t=56280

The free ver will tell you if you done it right as a test